Crown-type metal cap for sealing a metal bottle

ABSTRACT

A crown-type metal cap for sealing the mouth of a preferably aluminum metal bottle, the cap being formed by a laminar part of circular plan form, including an inner face and an outer face and provided peripherally with a closure skirt and, on the inner face, with a closure gasket including a peripheral lip. The cross-section of the peripheral lip is formed by a convex arc having at least one radius of curvature, adjacent to the closure skirt, the lip also including a side opposite the closing skirt, which can be a straight side or a curved side having a radius of curvature greater than that of the convex arc.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a crown-type metal cap for sealing bottles, particularly it relates to a crown-type metal cap for sealing the mouth of a metal bottle.

BACKGROUND OF THE INVENTION

At present, crown-type metal caps are formed by a laminar part of circular plan form having an inner face and an outer face, provided peripherally with a closure skirt and a closure gasket having a peripheral lip located on the inner side of the metal cap. The closure skirt is in turn provided with a plurality of radial projections and depressions interspersed while the peripheral lip of the closure gasket comprises one or more protrusions. These crown-type metal caps are used for sealing the mouth of a glass bottle containing a beverage, that may either be pressurized or not.

The crown-type metal cap to be applied to a glass bottle, offers a hermetic sealing, as the circular plan and the peripheral lip of the closure gasket are tight against the top ring of the mouth of the glass bottle when the cap is applied on it. The protrusions and depressions of the closure skirt of the crown-type metal cap are folded and pressed at the same time through a forming tooling against the ring of the mouth of the glass bottle and slightly below it, providing a proper grip.

The actual crown-type metal cap that is used to seal the mouth of a glass bottle is not suitable for sealing a mouth of a metal bottle, because the metal mouth of a bottle has a different configuration from the mouth of a glass bottle as shown in FIGS. 1, 2 and 3. The mouth of a glass bottle 10 shows a ring 11 having an external diameter D1 and an inner diameter D2 and a top rim 12 and inner rim 13 where at least one of these rims is flat, which helps the sealing by the appropriate seating of the peripheral lip of the closure gasket on said rims. In contrast, the mouth of a metal bottle 20 has a metal ring 21 having an outer diameter D3 and an inner diameter D4 and fully curved edge, so that the outer diameter D3 is generally equal to the inner diameter D1 of ring 11 of the glass bottle 10, while the inner diameter D4 is larger than the outer diameter D2 of ring 11 of the glass bottle 10.

In addition to this, the manufacturing process produces the mouth of the glass bottle to have a constant diameter and because of its material it has a strength that doesn't allow any deformation of the mouth during storage, transportation, filling and sealing of the glass bottle, which produces the proper seating and hermetic closure of the crown-type metal cap. The configuration of the mouth of the glass bottle is standardized by the “Glass Packaging Institute”. In contrast, the mouth of the metal bottle tends to deform during its proper manufacturing process, as well as in storage, transportation, filling and sealing of the metal bottle, which means that the diameter of the bottle mouth presents variations or irregularities that can lead to a non-hermetic closure of the traditional crown-type metal cap.

Therefore, the current crown-type metal cap that is used to seal glass bottles is not entirely favorable to seal metal bottles, since the closure gasket of the current crown-type metal cap is not adapted to compensate for variations present in the finish and the diameter of the mouth of the metal bottle, thus it is necessary to provide a crown-type metal cap with a closure gasket having a design which compensates for such imperfections in the mouth of the metal bottle.

SUMMARY OF THE INVENTION

In view of the above and in order to solve the limitations encountered in the crown-type metal caps, it is the object of the invention to offer a crown-type metal cap to seal the mouth of a metal bottle; this crown-type metal cap is formed by a laminar piece with a circular inner surface and an outer surface, provided with a closure skirt and a closing gasket with a peripheral lip located on the inner surface; the peripheral lip has a convex arc with at least one radius of curvature and adjacent to the closure skirt, and an opposite side to the closure skirt and this has a shape selected from a group consisting of a straight line, a curve with a radius of curvature greater than the radius of curvature of the convex arc, and combinations thereof.

BRIEF DESCRIPTION OF THE FIGURES

The characteristic details of the invention are described in the following paragraphs together with the figures related to it, in order to define to the invention but without limiting its scope.

FIG. 1 shows a side sectional view of a mouth of a glass bottle of the prior art.

FIG. 2 shows a side sectional view of a first embodiment of the mouth folded into a metal bottle of the prior art.

FIG. 3 shows a side sectional view of a second embodiment of the mouth folded onto the outer of a metal bottle of the prior art.

FIG. 4 shows a longitudinal sectional view of a crown-type metal cap according to the invention.

FIGS. 5A, 5B and 5C show sectional detail views of a first embodiment of a peripheral lip with one opposite side in straight line shape of a closure gasket of the crown-type metal cap according to the invention.

FIGS. 6A, 6B and 6C show sectional detail views of a second embodiment of a peripheral lip with one opposite side in a concave curve shape of a closure gasket of the crown-type metal cap according to the invention.

FIGS. 7A, 7B and 7C show sectional detail views of a third embodiment of a peripheral lip with one opposite side in a convex curve shape of a closure gasket of the crown-type metal cap according to the invention.

FIG. 8 shows a longitudinal sectional view of a crown-type metal cap located before sealing the mouth of a metal bottle according to the invention.

FIG. 9 shows a longitudinal sectional view of a crown-type metal cap sealing the mouth of a metal bottle according to the invention.

FIG. 10 shows a longitudinal sectional view of a half of a crown-type metal cap according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention refers to a crown-type metal cap useful for sealing the mouth of a metal bottle, where this metal bottle may be of aluminum or of any other type of metal appropriate to contain a pressurized or non-pressurized drink for human consumption.

FIG. 4 shows a longitudinal sectional view of a crown-type metal cap according to the invention. The crown-type metal cap 30 is shown in its previous state before closure to seal the mouth of a bottle. The crown-type metal cap 30 is formed by a laminar part of circular plan form with an outer surface 40 and an inner surface 50, provided with a closure skirt 60 and a closure gasket 70.

The crown-type metal cap 30 of the invention is made of metal sheets, preferably steel, having a thickness with a range from approximately 0.160 mm to approximately 0.251 mm.

The outer surface 40 is optionally coated with a pigmented or non-pigmented coating and on which, by lithographic process, can be printed an advertising, for example, the brand of the drink or the bottler. In an alternative embodiment, the inner surface 50 may be coated with a pigmented or non-pigmented coating which may give the crown-type metal cap 30 a distinctive character that allows to distinguish and/or identify it at a glance, from the perspective of this face, compared to other metal caps, either during manufacture, storage, distribution, marketing or once it has been discarded.

The closure skirt 60 is formed with a plurality of protrusions 80 interspersed with depressions 90 allowing its marginal folding over the mouth of a metal bottle to seal it.

The closure gasket 70 has a circular flat shape and is positioned on the inner face 50, so either it is attached or formed on the metal substrate or on the pigmented or non-pigmented coating placed on the inner face 50. The closure gasket 70 has a peripheral lip 100 which has a cross section formed of a convex arc 110 adjacent to the closure skirt 60 and a side 120 opposed to the closure skirt 60. The convex arc 110 has at least one radius of curvature, while the opposite side 120 may be a straight side or a curved side, in case this side is curved it must have a radius of curvature much larger than the radius of curvature of the convex arc 110.

The closure gasket 70 is made of thermoformable material, either PVC or PVC-free, or any other substitute material for PVC. The closure gasket 70 has an inner diameter D5 from approximately 19.05 mm to approximately 21.5 mm measured at the edge of the opposite side 120 of the peripheral lip 100 and an outer diameter D6 from approximately 23.5 mm to approximately 24.8 mm measured at the edge of the convex arc 110 of the peripheral lip 100. The peripheral lip 100 has a height H1 of approximately 0.95 mm to approximately 1.05 mm.

FIGS. 5A, 5B and 5C show sectional detail views of a first embodiment of a peripheral lip having one opposite side in straight shape of a closure gasket of the crown-type metal cap according to the invention. In this embodiment, the peripheral lip 100 has an opposite side 120 in straight shape forming an angle from 85° to 95° relative to the horizontal axis of the crown-type metal cap 30, with the representation of FIG. 5A at an angle of 90°, in FIG. 5B at an angle bigger than 90°, and in FIG. 5C at an angle smaller than 90°. This range of angles allows and facilitates the peripheral lip 100 to deform or bend towards the inside of the crown-type metal cap 30 to engage and seat on the curved edge of the ring 21 of the mouth of the metal bottle 20 when the crown-type metal cap 30 is positioned and sealed on the metal bottle mouth 20.

FIGS. 6A, 6B and 6C show sectional detail views of a second embodiment of a peripheral lip with one opposite side in concave curve shape of a closure gasket of the crown-type metal cap according to the invention. In this embodiment, the peripheral lip 100 has an opposite side 120 in concave curve shape with a radius of curvature greater than the radius of curvature of the convex arc 110. This radius of curvature allows and facilitates the peripheral lip 100 to deform or bend towards the inside of the crown-type metal cap 30 to engage and seat on the curved edge of the metal bottle mouth when the crown-type metal cap 30 is positioned and sealed on the metal bottle mouth.

FIGS. 7A, 7B and 7C show sectional detail views of a second embodiment of a peripheral lip with one opposite side in convex curve shape of a closure gasket of the crown-type metal cap according to the invention. In this embodiment, the peripheral lip 100 has an opposite side 120 in convex curve shape with a radius of curvature greater than the radius of curvature of the convex arc 110. This range of angles allows and facilitates the peripheral lip 100 to deform or bend towards the inside of the crown-type metal cap 30 to engage and seat on the curved edge of the metal bottle mouth when the crown-type metal cap 30 is positioned and sealed on the metal bottle mouth.

FIG. 8 shows a longitudinal sectional view of a crown-type metal cap located before sealing the mouth of a metal bottle according to the invention. At the time of positioning the crown-type metal cap 30 on the mouth of the metal bottle 20 and prior to closing, the peripheral lip 100 of the closure gasket 70, in particular its convex arc 110, sits on the inner edge of the ring 21 of the mouth of the metal bottle 20, which helps the crown-type metal cap 30 automatically to align concentrically on the mouth, thereby offsetting any irregularities present in its circular shape. This concentric alignment of the crown-type metal cap 30 is facilitated by the curvature of this convex arc 110 of the peripheral lip 100 when entering in contact with the curvature of the inner edge of ring 21 of the mouth of the metal bottle 20, providing a single contact point along the mouth of the metal bottle 20 which circumscribes a circular line between the peripheral lip 100 and the ring 21 of the metal bottle 20.

FIG. 9 shows a longitudinal sectional view of a crown-type metal cap sealing a mouth of a metal bottle according to the invention. When the crown-type metal cap 30 is closed on the mouth of the metal bottle 20, the peripheral lip 100 of the closure gasket 70 is deformed by crushing, thus promoting a material flow, mostly towards the center of the crown-type metal cap 30, that is, the opposite side 120 of the peripheral lip 100 is deformed so as to touch the base surface of the closure gasket 70, while the convex arc 110 of peripheral lip 100 is deformed so that it adopts the curvature of the edge of ring 21 even when the edge has imperfections, thereby hermetically sealing the mouth of metal bottle 20. This phenomenon of deformation and attachment to the peripheral edge of the mouth of metal bottle 20 is facilitated by the fact that the peripheral lip 100 has an asymmetric cross-sectional shape that facilitates its deformation by displacement of the material to the side with less resistance and matter content, which in this case is the opposite side 120.

FIG. 10 shows a longitudinal sectional view of a half of a crown-type metal cap according to the invention, wherein the peripheral lip 100 has a convex arc 110 defined by a major curve with a radius of curvature R1 and a minor curve with a radius of curvature R2. Radius of curvature R1 has a dimension from approximately 1 mm to approximately 1.2 mm, while radius of curvature R2 has a dimension from approximately 0.25 mm to approximately 0.29 mm, defining between the two curves, major and minor one, a stepping at an angle β from approximately 9.50° to approximately 9.60°.

The minor curve in the upper peripheral lip 100 has the function of facilitating the deformation by compression of peripheral lip 100 as well as facilitating the manufacture of the closure gasket 70, in particular including peripheral lip 100, as it prevents the formation of burrs at the moment of demolding of the tooling.

Peripheral lip 100 has a height H2 from approximately 1.65 mm to approximately 1.75 mm from the base of the closure gasket 70 to the upper edge of the convex arc 110 and a height H3 from approximately 0.95 mm to approximately 1.05 mm from the base of the peripheral lip 100 to the top of the convex arc 110. Closure gasket 70 in its central part has a thickness H4 from approximately 0.18 mm to approximately 0.22 mm.

Based on the alternatives described in these embodiments, it is considered that modifications to each of the described embodiments as well as alternative embodiments of application will be considered obvious to a person skilled in the art of the art under the present description. Therefore, it is considered that the claims cap said modifications and alternatives that are within the scope of the present invention or its equivalents. 

1. A crown-type metal cap comprising a laminar part of circular plan form, including an inner face and an outer face and provided peripherally with a closing skirt and, on the inner face, with a closure gasket including a peripheral lip, characterized in that said peripheral lip has a cross-section comprising: a convex arc having at least one radius of curvature, adjacent to the closure skirt; a side opposite the closing skirt having a shape selected from a group consisting of a straight line, a curve with a radius of curvature greater than the radius of curvature of the convex arc, and combinations thereof; and wherein said crown-type metal cap serves for sealing the mouth of a metal bottle.
 2. The crown-type metal cap of claim 1, characterized in that said opposite side of the peripheral lip has a straight shape and an inclination angle from 85° to 95° in relation to the horizontal axis of the crown-type metal cap.
 3. The crown-type metal cap of claim 1, characterized in that said opposite side of the peripheral lip has a convex curve shape.
 4. The crown-type metal cap of claim 1, characterized in that said opposite side of the peripheral lip has a concave curve shape.
 5. The crown-type metal cap of claim 1, characterized in that said convex arc of the peripheral lip has a major curve and a minor curve.
 6. The crown-type metal cap of claim 5, characterized in that said major curve has a radius of curvature from 1 mm to 1.2 mm.
 7. The crown-type metal cap of claim 5, characterized in that said major curve has a radius of curvature from 0.25 mm to 0.29 mm.
 8. The crown-type metal cap of claim 1, characterized in that said closure gasket has in inner diameter from 19.05 mm to 21.5 mm measured on the edge of the opposite side of the peripheral lip.
 9. The crown-type metal cap of claim 1, characterized in that said closure gasket has an outer diameter of 23.5 mm to 24.8 mm measured on the edge of the convex arc of the peripheral lip.
 10. The crown-type metal cap of claim 1, characterized in that said the peripheral lip has a height from 0.95 mm to 1.05 mm.
 11. The crown-type metal cap of claim 1, characterized in that has a sheet thickness from 0.160 mm to 0.251 mm.
 12. The crown-type metal cap of claim 1, characterized in that said metal bottle that is being sealed is a bottle made of aluminum. 